1. Alcohol Toxicology
Chapter 9

2. What is Alcohol???
Definition – a family of closely related chemicals whose molecules are made of carbon, hydrogen and oxygen
Examples – methyl alcohol (methanol), isopropyl alcohol (isopropanol), butyl alcohol and ethyl alcohol (ethanol)*

3. Ethanol is the type of alcohol contained in
popular beverages
Chemical Formula for Ethanol:
C2H5OH: H H H C C OH H H

4. IS Alcohol… A food? YES A drug? A poison? It all depends on the dose!
Ethanol’s LD 50 in rats is 13.7 g/kg of body weight
LD 50 = dose that is lethal for 50% of population

5. Toxicology of Alcohol
Alcohol is absorbed through the stomach and intestine
Once absorbed, alcohol is:
Oxidized- in liver by alcohol dehydrogenase—turned into acetic acid
Excreted- by breath, perspiration, and kidneys—turned into carbon dioxide and water

6. Alcohol Absorption 20% is absorbed through the stomach
80% diffuses into the blood through the walls of the small intestine
Now the alcohol can be distributed to other body parts

7. Parts of the brain affected by Alcohol
Alcohol 1st affects the forebrain and moves backward
Last affected is medulla oblongata

8. Factors that Affect Alcohol Absorption
Time of consumption
Type of alcoholic beverage
Presence of food in stomach

9. Toxicology of Alcohol Alcohol intoxication depends on
Amount of alcohol consumed
Time of consumption
Body weight
Rate of alcohol absorption

10. Example: an Irish Whiskey that is 100 proof
CALCULATING ALCOHOL CONTENT
OF BEVERAGES
Proof is actually double the alcohol
content
Example: an Irish Whiskey that is 100 proof
has a 50% ethanol content

11. Size Can be Deceiving!!
Beer – 12 oz. 4% alcohol (8 proof) is equivalent to 0.48 ounces of pure ethanol
Wine – 4 ounce 12% alcohol (24 proof) is equivalent to 0.48 ounces of pure ethanol
Whiskey – 1 shot , % alcohol (80 proof) is equivalent to 0.5 ounces of pure ethanol

12. = = SO… Ingestion of any of the above results in equal
1 ¼ oz. whiskey
12 oz. beer
4 oz. wine
Ingestion of any of the above results in equal
amounts of ethanol entering the system

13. Fate of Alcohol Alcohol is absorbed into the bloodstream
Distributed through-out the body’s water
And finally eliminated by oxidation and excretion

14. Oxidation of Alcohol in the Liver
The Liver Burns Ethanol – chemically combines it with oxygen
The process is aided by the enzyme alcohol dehydrogenase
95%-98% is oxidized to CO2 and H2O in the liver

15. Oxidation of Alcohol in the Liver
Acetyl aldehyde
Alcohol
CO2 + H2O + Energy
Due to metabolism, the average person’s BAC drops about 0.015% per hour

16. Fate of Alcohol Con’t Note:
Oxidation is the combination of oxygen and alcohol to produce new products by the liver
Elimination is removing alcohol from the body in an unchanged state; normally excreted in breath and urine

17. Alcohol in the Circulatory System
Measuring the quantity of alcohol in the blood system determines the degree to which someone is drunk
Two methods of making this measurement
Measurement of alcohol content in blood
Measurement of alcohol in breath

18. Circulation and Alcohol

19. Circulation Definitions
Artery—a blood vessel that carries blood away from the heart
Vein—a blood vessel that transports blood toward the heart
Capillary—a tiny blood vessel—walls exchange materials between blood and tissues
Alveoli—small sacs in lungs—exchange vapors between breath and blood

20. Circulation Con’t
Note: If alcohol is present, it will be passed from the blood into the alveoli where it will be passed on to the mouth and nose during the act of breathing.
Evidence has shown that the ratio of alcohol to alveoli air is approx to 1—This is a basis for relating breath to blood-alcohol concentration.

21. Analysis of BAC
Breath Tests
Field Sobriety Tests
Blood Tests

22. Breath Tests
A breath test reflects the alcohol concentration in the pulmonary artery.
One instrument used for breath tests is called The Breathalyzer.
The Breathalyzer is a device for collecting and measuring the alcohol content of alveolar breath.

23. The Breathalyzer

24. The Breathalyzer Con’t
The Breathalyzer traps 1/40 of 2100 milliliters of alveolar breath.
Since the amount of alcohol in 2100 milliliters of breath approximates the amount of alcohol in 1 milliliter of blood—the Breathalyzer in essence measures the alcohol concentration present in 1/40 of a milliliter of blood.

25. Breathalyzer Con’t
Once the alveolar breath is trapped it is allowed to undergo a chemical reaction:
2K2Cr2O7 + 3C2H5OH + 8H2SO4  2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11H2O
The Breathalyzer indirectly determines the quantity of alcohol consumed by measuring the absorption of light by potassium chromate before and after its reaction with alcohol, using the principle of spectrophotometry
Potassium dichromate
Ethyl alcohol
Sulfuric acid
Chromium sulfate
Potassium sulfate
Acetic acid
Dihydrogen oxide

26. Other Breath Tests Infrared breath-testing instrument Fuel cell
Note: These instruments are used more recently because they don’t depend upon chemical reagents and are entirely automated.

27. Infrared-Breath Test
Uses the principle that infrared light is absorbed when shined on alcohol
Essentially, the infrared light passes through a chamber where it will interact with the alcohol and cause the light density to decrease.
The decrease in light intensity is proportional to the concentration of alcohol present in the captured breath

28. Fuel Cell—Breath Test
A fuel cell converts a fuel and an oxidant into an electrical current.
In this test, the breath alcohol is the fuel and atmospheric oxygen acts as the oxidant.
Alcohol is converted, generating a current that is proportional to the quantity of alcohol present in the breath.

29. Infrared and Fuel Cell Breath Tests
Infrared Breath Test uses infrared wavelengths to test for alcohol or other interferences in the breath
Fuel Cell Test converts fuel (alcohol) and oxygen into a measurable electric current

30. Field Sobriety Testing
Two reasons for the field sobriety test:
Used as a preliminary test to ascertain the degree of the suspect’s physical impairment
To see whether or not an evidential test is justified.

31. Field Sobriety Testing Methods
Field sobriety testing consists of a series of psychophysical tests and a preliminary breath test (typically done with a handheld fuel cell tester)
These tests are preliminary and nonevidential in nature—they only serve to establish probable cause requiring a more thorough breath or blood test.

32. Field Sobriety Tests Horizontal Gaze Nystagmus
Involuntary eye jerk as eye moves horizontally
Walk and Turn (divided attention tasks)
One-Leg Stand

33. Alcohol and the Law 1939-1964: intoxicated = 0.15% BAC
At least we don’t live in France, Germany, Ireland, or Japan (0.05%) or especially Sweden (0.02%)!
Alcohol and the Law
: intoxicated = 0.15% BAC
1965: intoxicated = 0.10% BAC
2003: intoxicated = 0.08% BAC

34. Alcohol and the Law
Try the drink wheel:

35. Schmerber v. California 1966
Fifth Amendment Violation?
The Fifth Amendment protects against self incrimination
Fourth Amendment Violation?
The Fourth Amendment protects against unlawful search and seizure

36. The End